MODAL DECOMPOSITION AND BEHAVIOR OF FREE VIBRATION RESPONSE WITH GROUNDING AND UPLIFTING

Abstract

 According to some studies of uplift building behavior from dynamic analysis and shaking table test of small scale building model, it has been shown that higher mode vibration occurs in the frame during uplift. Particularly if soil support spring stiffness becomes hard, higher mode vibration will also grow large. It was easy to image about relation between the stiffness of the ground spring and higher mode vibration, but there was no theoretical explanation of how this higher mode vibration is generated and amplified. The aim of this study is to find physical principle about mechanism of amplifying of higher mode vibration and relationship between ground spring stiffness.